I'm getting conflicting answers here, my store tells me to use my water softened water as I wont have to use the pillow and the tub will be ready faster. Someone online had posted (i'm having trouble finding it now) that a water softener throws off the chemistry of the water and causes other issues. Now we use potassium chloride not sodium so I'm wondering if that would be ok since we aren't adding additional sodium atoms to the water ?